356 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



the GoDodactyli scattering in all directions, and the masses of yellow eggs which were spattered 

 over the large rock which I had used as an anvil ; but the problem was solved, and I went home 

 and to bed, confident that I should next day get all the embryological material I needed. 



As shown in PI. iii, the animal molds or shapes the mass of eggs into a hemispherical cap, 

 which fits over the convexity of the hind body and lies between it and the stone wall of the bur- 

 row. The parent reaches out to snatch at passing j)rey, but so long as she is undisturbed she 

 remains in the burrow. When the burrow is broken open she quickly rolls the eggs into a ball, 

 folds them under her body in a big armful, between the large joints of her raptorial claws, and 

 endeavors to escape with them to a place of safety. The promptness with whicli this action is per- 

 formed would seem to indicate that it is an instinct which has been acquired to meet some danger 

 which frequently presents itself. It would seem as if a cave in a solid rock were a pretty safe 

 refuge from all enemies except a naturalist with a geological hammer, and it is difficult to say 

 what the accident is which has thus been provided against. The larger beads of growing coral 

 are often broken off by the waves, and loose fragments of rock are overturned by severe storms, 

 and it is possible that, when alarmed by a violent shock, it flees from its cave to escape the 

 danger of being crushed when the rock is torn from its place and turned over. At any rate its 

 habit is the i-everse of that of most burrowing animals, for they usually retreat to the depths of 

 the burrow when alarmed. This is true of all the Stomatopods which I have had an opportunity 

 to obsers'e except this species, and the chief use of the burrow of t'^quUla empusa is for refuge in 

 danger, while LysiosquiUa excavatrix darts down its burrow at the least alarm and can not be 

 driven out even when the sand has been dug up on all sides of it. 



The Metamorphosis of Gonodactylus chieagra. 



That feature of the life of Stomatopods upon which new data are most to be desired is the 

 history of the early larval stages, and an abundant supply of the eggs of GonoductyluH chiragra 

 rendered it an easy matter to obtain this history for that species. I also obtained a complete series 

 of eggs for studying the embryology, but, as a few preliminary sections showed that this was of 

 slight interest and that there is no essential ditterence from other Macroura as regards the egg 

 embryology, this subject was not studied. 



Most of our knowledge of the metamorphosis of Stomatopods is based upon the comparative 

 study of collections of alcoholic specimens, and the direct observations on living larvae are very 

 scanty. In 1SS2 Faxen published an account (Selections from Embryological Monograi)lis com- 

 piled by Alexander Agassiz, XA^alter Faxon, and E. L. Mark, I Crustacea, Cambriilge, 18S2, Bull. 

 Mus. Com]). Zotil., Vol. ix. No. 1, PI. viii. Figs. 2 and 3) of observations made three years before 

 upon a young Squilki empusa which he had reared from an Alima larva; and in a par|)er which 

 was published iu 1870 I described (On the larval stages ol' Squilla cmpiisa) a sei'ies of similar larv;B 

 which I had studied while they were alive, and which was suthcieutly complete to warrant the 

 statement that they were the young of SquiUa empusa, and that this species probably hatches from 

 the egg iu the Alima stage. In my report on the Challenger Stomatopods (IJeport of the Scientific 

 Results of the Voyage of H. M. S. Challenger during the years i87o-7tJ, xvi, part XLV, I8SG) I 

 have given an account of the metamorphosis of Lysiosquilla excavatrix which I had reared at 

 P>eaufort, N. C. : but except for these observations our knowledge of Stornatopod metauior|)hosis 

 rests upon the comparative study of preserved specimens, and, while the series which are picked 

 out from miscellaneous collections sometimes present pretty satisfactory evidence as to the adults 

 which they represent, this sort of indirect evidence can not be conclusive. 



Large and varied collections of larvie have been compared for the purpose of selecting those 

 which form stages in the same series, and of ascertaining as accurately as possible the adult aflini- 

 ties of theoldest larva-, by Claus (Die Metamorphosen der Squilliden, Abhandl. d. I: Gesellsch. d. 

 Wiss., Gottingen, Bd. xvi, pp. 1-55, Pis. i-viii, 1871) and myself (C'/(«7/e«(/e/- Rep., pp. 81-11-1). My 

 own report was, so far as this subject goes, a supplement to Claus's work, for in its preparation I 

 availed myself of his methods and results, amplifying and completing many of his observations, 

 and confirming some of his results and correcting others. Combining his work with my own, I 

 devoted a chapter of my report to the discussion of the larviB, and gave a scheme or outline of 

 the probable metamorphosis of each genus of adult Stomatopods. 



V. 



