1888.] G. M. Giles— JV^o/e.s on the AmpTiipoda of hulian Waters. 231 



first and last. Each gill plate consists of a flattened lamina of consider- 

 able lengthjthe longest being nearly as long as twice the depth of the body. 

 From each face of this primary lamina, spring secondary laminae ar- 

 ranged in regular alternation on either side to the number of 20 or 30 

 on each face. These secondary laminae are of considerable area, the depth 

 of the largest being quite half the length of an average thoracic segment. 

 Gills of so complicated a structure as this are rare amongst the Araphi- 

 poda, and their presence in our species is no doubt connected with its 

 mode of life. Burrowing as it does in thick mud, its anterior abdominal 

 appendages cannot be kept in the usual rapid vibration which in most 

 species maintains a free current of water through the subthoracio 

 hollow. Such a current being unobtainable, the difficulty is met by the 

 great increase of available gill surface secured by the complex branchial 

 structure already described. 



Organs of Reproduction. — Although a very large number of speci- 

 mens was obtained, all appear to belong to the female sex, all presenting 

 the same external characteristics, and all the specimens that were dis- 

 sected having the same form of generative gland. Apparently the 

 animals were not breeding at the time of the haul, as, although the 

 ovaries of most of those sectionized contained young ova, none carried 

 eggs beneath the thorax. The ovaries consist of a simple tube bent on 

 itself and occupying nearly the entire length of the thorax, so that a 

 typical section exhibits four tubes cut across and disposed in a semicircle 

 below the alimentary canal ; of these the outer pair appear to be the 

 glandular and the inner, the duct portions of the organs. Such ova as 

 were met with in this latter portion of the tube were enveloped in a 

 voluminous ovoid coating of albuminous material. The flexure of the 

 ovarian tube takes place at the anterior end of the thorax, so that its 

 blind commencement is in the most posterior portion of the region. In 

 one series of sections, the organ presents a suspicious resemblance to 

 a sperm-producing gland, in other respects differing in no way from the 

 usual type, while no ova could be made out in any portion of the series 

 of sections. It may be that this is a male specimen, but, if this be 

 the case, the organs of both sexes closely resemble each other, even 

 to the detail of the double tube bent on itself. 



3. MiCRODEUTOPUS MEGNiE, n. sp., PI. YII., Figs. 1 — 4. 



The species described below was taken in the surface net in the 

 turbid water (about 6 fathoms) of the Megna Shoals. 



The animal, which is 4^ mm. long, is of a dirty white colour, 

 and the intestinal canal often shews through the body as a greenish 

 streak. 



