602 SCIENTIFIC RECORD FOR 1884. 



two groups, oue restricted to the " Ocypodiacea," aud the other com- 

 prisiug the Gelasimi and related genera as well as the Pinuotherians, 

 Whether such a combination is natural may be questioned, but a re- 

 newed examination of the detailed structure of the several types may 

 be demanded as the result of the investigation. 



The muscles of the stomach and its armature are described in con- 

 siderable detail, both in respect to their connections and functions. 

 The median tooth is advanced forward and the two lateral pieces are 

 approximated at their anterior extremities. The median tooth is lodged 

 in an angle between the lateral, and all together are worked for a sec- 

 ond to grind the food taken in, then there is relaxation, and then again a 

 new contraction, and so on. The urocardiac piece serves to maintain 

 the food in the special region. M. Mocquard thinks that these move- 

 ments are not reflex, but voluntary, as Cuvier had already contended. 



The muscles which work the gastric pieces are innervated by nerves 

 issuing from the stomatogastric. The functions of this are analogous 

 to those of the sympathetic nerve, and are complex ; in one place 

 it is subservient to sensation and involuntary movements, and it also 

 regulates voluntary movement as of the labrum and oesophagus; per- 

 haps even it has filaments of special sensibility. Several questions of 

 this kind are left in doubt, and M. Mocquard disclaims having ex- 

 hausted the subject. {Revue Scientijiqtie, t. xxxiv, pp. 204, 205.) 



Peculiarities of deep-sea Crustaceans. — In asummary of the "Crustacea 

 of the Albatross dredgings in 1883," Prof. Sidney I. Smith has enunci- 

 ated some generalities respecting the characteristics of the deep-sea 

 crustaceans. A striking characteristic is their red or reddish color. 

 "A few species are apparently nearly colorless, but the great majority 

 are some shade of red or orange," and he had met with " no evidence 

 of any other bright color." A few species "from between 100 and 300 

 fathoms are conspicuously marked with scarlet or vermilion, but such 

 brighter markings were not noticed in any si)ecies from below 1,000 

 fathoms. Below this depth, orange red of varying intensity, is ap- 

 parently the most common color, although in several species the color 

 was an excessively intense dark crimson." 



The eyes of the abyssal species are even more remarkable than their 

 colors. In sixteen species especially examined, the eyes were present 

 in the normal position, and distinctly faceted. In six they were well 

 developed, but smaller than in average prawns, and of a black color. 

 In one the eyes were "black, but conspicuously smaller than in the 

 allied shallow-water species." In another they were "black, and of 

 moderate size " ; and instill another they were " apparently black, or 

 nearly black, and small." In one they were "nearly colorless in alco- 

 holic specimens, and rather larger than usual in the genus, but con- 

 siderably smdller" than in related species found at less depth. In three 

 they were "not conspicuously different in size from those of allied shal- 



