438 GEOLOGICAL SURVEY OF THE TEERITOEIES. 



nerves or the oesophageal commissure. Clans also likens the stalked 

 eyes to those of Mysidoe. In Nebalia no ears have been found. 



In the digestive canal, says Claus, we have a quite specific peculi- 

 arity, together with approximations sometimes to the Amphipoda and 



Isopoda, and sometimes to the Mysidce and 

 Fodoplithalmata. The short up curved 

 oesoi)hagus leads into a stomach with a 

 complicated chitinous armature, in which 

 an anterior and a posterior division can 

 be distinguished. While in form and rel- 

 ative size of both parts there is a resem- 

 blance to the stomach of Amphipoda, so 

 we may also observe in the position and 

 number of the chitinous plates of the ap- 

 paratus for triturating the food a true re- 

 liS-^^^^^^i^ semblance to the Isopoda, but also to the 



luoioenlarsedtosliow the ganglion cells, pyloric divisioU Of the Stomacll Ot the My- 



Author del. sidfB, whosc capacious and sack-like ex- 



l^anded cardiac division seems to correspond to the differently-formed 

 03Soi)hageal portion of Nebalia. The slender intestinal canal along its 

 whole course is surrounded with a uniform layer of circular muscles, 

 and on the inner side of the tunica propria is surrounded with a thick, 

 fatty layer of epithelium; it reaches to the begiuning of the last seg- 

 ment, which is nearly filled by the muscular rectum {afterdarm). At 

 the origin of the intestine (chylusdarm) arise two anteriorly and four 

 (two larger than the others) posteriorly-directed liver-tubes; these four 

 latter-named tubes or coeca are attached by a richly-developed fatty 

 tissue of the serous membrane to the intestinal walls, and reach far 

 into the abdomen. The two anteriorly-directed coeca reach to the anteu- 

 nal segment, and are frequently wholly enveloped by the fat corpuscles 

 of their serous coat. (Compare our figure of N. hipes^ PI. XXXVII, 

 fig. 6.) 



" The two anterior biliary cceca manifestly correspond to those which 

 we so often, though not always, meet with in Podophthalmatous larvae 

 (Phyllosoma, Sergestes-larvse, &c.), but which, however, exist only in a 

 rudimentary state in many Edriophthalma. The histological structure 

 of the liver-tubes agrees closely with that of the intestine ; the circular 

 muscles still remain, though scattered aud absent at intervals. The 

 epithelium consists of smaller aud larger cells filled mostly with large, 

 fat cells, whose secretious, like a fluid tinged yellowish, fills the often 

 widely distended cavity of the canals. Now, arising in a remarkable 

 way on the under (or lower, unterer) side of the intestine are two long 

 ascending appendicular tubes, for the most i>art embedded in the fat body, 

 which is enveloped by fat cells. The hinder intestinal api)endages of 

 Xebalia, in which we could not detect the colored secretion of the liver- 

 tubes, remind one of the so-called malpighian tubes of the Gammaridse, 

 which arise at the beginning of the much longer rectum which passes 

 through the three terminal segments of the abdomen. In IsTebalia the 

 relatively short rectum, by means of the numerous muscular bands sus- 

 pending it from the intestine, performs the movements so generally ob- 

 served in Phyllopods, by which the water is drawn in in an almost ryth- 

 mical manner aud then expelled. The anus, concealed by two triangu- 

 lar chitinous jilates of the terminal segment, opens between two small 

 lateral flaps, which closely resemble those in the inner side of the furcal 

 appendages of the Protozoea larva of Pena3us. 



" Of the pair of tubular glands which serve in the body of Phyllopod 



