I am much oblig’d to you for your letter of the 8th of Dec[em]b[e]r last, full of most excellent remarks.
I shall endeavour to clear up some difficulties that arise with you in my Plate of the Lepas’s.
Fig. 3. is taken from d’Argenville, fig. H. & I. Tab. 30, he describes it to have 5 valves, but I have never seen it. I have inserted it to shew it is not the same with my Fig. 2.
Fig. 7. and Fig. 7. a. is the Pediculus Ceti or Diadema Turcorum, and always of a subrotund figure, and a very different species from Fig. 12. which is your Testudinaria.
Figs. 8. & 9. approach near to one another, but Fig. 9. is conical, and Fig. 8. subcylindrical.
Fig. 10. is a distinct species chiefly found in the Mediterranean Sea, the summits of the valves are pointed and the opening wider than Fig. 8, differing much from it both in colour and habit, which is very difficult to describe, unless you saw both species together.
Fig. 11. is composed of 6 valves, as it is not easily distinguished without a Lens Glass, it could not be well expressed in the engraving. The Valves are composed of minute quills or hollow tubes, their openings to be seen plainly at Fig. 11. a. This is evidently a distinct species. The latter I had from P[eter] Collinson; the Groupe Fig. 11. from D[octo]r Fothergill.
Fig. 12. is much more compressed, even upon comparing it with different specimens of the same sixe with Fig. 13. this last being much higher, even twice as high in proportion as. Fig. 12.
Fig. 14. I believe may owe its obliquity to accident, but this is their general form when they are found adhering to muscles, but their opercula differ much in their having longer horns; and their shells in proportion to their size are more slender and thin than that at Fig. 8.
Fig. 15. These are very thick and more oval shaped than Fig. 20. with a much smaller opening. The valves of these are not pointed at top like that.
Fig. 16. I have not seen this, only I have described it from the Fig[ure] of M[iste]r Borlace in his Natural History of Cornwall lately publishd. I have wrote to him about it in order to satisfy you.
Fig. 17. is the common small Lepas, that grows on all our Rocks & Shells on the
Coasts of the British Isles. It is rarely ever found larger than here represented, and
never so large and regular as Fig. 20. So that it must be a different species, especially
as I have minutely examined and compared both with the best magnifying glasses.
From the animal of Fig. 17. I have describd the Figure of the Animal Triton, which I
shall send you by the first opportunity in Spring. It is drawn with great exactness.
These animals, which we have in great abundance on our Oysters at this Season of
the year, have the lower part of their shells filld with their ova or spawn, which
possesses full half the shell. When these animals[a][a] : MS 1 animals [added above the
line] are separated from their shells, and put into the watch glass with salt put to the water, they will live many hours, and in that[b][b] : MS that [added above the
line] state I viewd and had them delineated from the Microscope.
These as well as most of the Lepades Sessiles, except those at Fig. 7. a. & Fig. 12. & 13. have a base shell of a circular figure (which I have not observd remarkd before), to which the 6 valves are united, as they are to one another.
Fig. 18. Is a true Multivalve of 6 Valves with the base, this was found adhering to a large Species of Muscle brought to my late Friend Arthur Pond, F[ellow] [of the] R[oyal] S[ociety], from Greenland.
Fig. 19. Is a species of Lepas found adhering to Keratophytes near the Straits of Gibraltar. The base of this grasps and embraces the slender twigs of these Zoophytes, and as the succession of the young progeny arises up to encrease and extend the parents animals, they enclose these Lepades all but the openings, as you may observe in the 3 figures on the Keratophyte at Fig. 19. a.
The Fig. 19. is one of them laid bare from the animal of the Keratophyte.
Fig. 20. I found in the Musaeum Britannicum collected by S[ir] Hans Sloane. It is extremely curious and perfect, and much more regularly disposd in its valves than any I have seen. It appears nearest to the Spec[imen] N. 8.
To conclude, I think you are extremely right in not adopting too many species, and I am afraid too many are only varieties. So shall leave this matter intirely to your judgment.
Since I wrote to you, I have had[c][c] : MS had [added above the
line] an opportunity of examining the Cochineal Insects, both Male and Female. The Female I rec’d alive from Carolina, from whence I expect a good many on the Cactus Opuntia for you. I have desird D[octo]r Garden to be exact in the changes of both, and to be sure to send me some for you.
I made a few Observations on these that I rec’d. The Females were alive, and the
smaller they were, their Legs and Antennae were longer in proportion. You have
describd them very well. Of the Males I found 2 dead, one on the Plant, one in Spirits
of wine. Their wings I believe must have been erect, when alive, but lay flat down when
dead. The head is prominent with longer Antennae than the females, and
Moniliformes. There is a small trunk like the beak of a bird from the head, but
depressd, the body longer and slenderer and a point arising from the Tail or Abdomen.
I dissected a little bag in which was a male Cochineal fly.[d][d] : MS fly [added above the
line] This explaind the form of the beak, and confirmd me that the Antennae of the sexes differ in form.
The Females after Impregnation grow torpid, and spin themselves a covering of a
fine white Web, where they lie till they are brushd off to be dried for use, or bring forth
their Young. The Males that I found were very small. I suppose they die soon after they
have answered the intentions of nature. The females when grown to the maturity of
bringing forth their young, have 6 very smal[e][e] : MS have six very [added above
the line] leggs, and two Antennae, with a trunk, between the 2 forelegs, all[f][f] : MS 1 all [added above the
line] so small that the Microscope must assist us to discover that this oval mass is an Animal. I had several of them preservd in spirits, and could easily discover that it spins its threads double like silkworm. I cut open several of them, and found them full of Eggs, impregnated and ready to send forth young animals. I put several of the Cochineal Insects from N[ew] Spain, used in dying Scarlet, into warm water, and after they had lain 12 hours to soak, they swelld up to nearly the same form with the Carolina Insects. When I cut these open, they afforded from 60 to 100 Eggs or[g][g] : MS 1 Eggs or [added above the
line] Young ones. The richness of the Colour seems to depend on the young Insects in the Eggs, as appeard to me in the Microscope.
I am obligd to you for your method of preserving of Seeds. I have sent some copies of it to the East Indies for Trial to be made.
I must now freely give you my opinions. I tried my Thermometer in the Mixture of
Salts you were pleasd to fix the proportion of, I mean both proportions, and I found it
did not affect it, for as soon as the Salts became of the same temperature with the Air
in the Room where the experiment was tryd, the Thermometer did not move higher or
lower; though coverd by the Salts. I imagine the use of the Salts is to prevent a
putrefactive fermentation in the Seeds.[h][h] : MS 1 in the Seeds [added above
the line] For, unless during the dissolution of Salts, I cannot find any cold air generated by any kind of Salt.
I lately tried some experiments on the Acorns of the common Quercus, and found that wax, rosin, or[i][i] : MS 1 <and> or a mixture of wax, resin, & pitch, were the best coverings to preserve seeds, that perspire much; for Gum Arabick, Senega, and Clay, usd separately on different acorns, did not answer the purpose, the Cotyledons or Kernels being quite dried up, and rendered unfit for Vegetation. The others secured the Cotyledons perfectly sound, as if just fallen from the trees. I kept the acorns in a dry box in a Room where a fire was kept every day, from the latter part of October to the present time. N.B. the perspiration of the acorns prevented the Wax, resin, or mixture to stick; so that the coverings came off easily. This method may preserve Tea Seeds, Mangoes, Spices of several sorts, sound, in long Voyages, if kept cool in the Ship’s ballast, in your mixture of Salts. Sir, your Obedi[ent] Serv[ant]