BY WILLIAM A. HASWELL, M.A., B.SC. 677 



was found in a separate tube. All of them seemed almost 

 incapable of motion, the utmost movement to be observed being 

 very feeble flexions and extensions of the limbs. 



The embryos on examination showed two principal stages. 

 In the first of these (pi. XXXVII., fig. 4) the ventral plate 

 has become segmented, but there are no appendages ; in the 

 second (fig. 5) the appendages are all represented ; the larva at 

 this stage having very much the appearance of that of Aselhis ; 

 and it is specially noteworthy that the flexure of the larva, as in 

 the genus just named and other " normal " Isopoda, is towards the 

 dorsal side. The dorsal organ (d.) is a small lobed body not pro- 

 jecting beyond the outer larval membrane. On either side of it is 

 a remarkable jointed larval appendage (e.) arising from the middle 

 of the lateral surface of the larva and directed outwards and dorsad. 

 No similar appendages are known to exist in any other Edri- 

 ophthalm ; but whether they point to the former existence in the 

 Edriophthalm larva of embryonic locomotive appendages of which 

 the ordinary paired " dorsal organ" may be a still further reduced 

 remnant, or whether they are simply developed for the attachment 

 of the larva to the pinnate hairs of the abdomen of the female a 

 further study of their structure and relations will be necessary to 

 decide. They are still present in a rather later stage of develop- 

 ment than that represented in figure 5, after the alimentary canal 

 and hepatic lobes have become clearly distinguishable. 



ElSOTHISTOS VERMIFORMIS. 



The general form of the body is narrow, almost cylindrical, with 

 a slight amount of dorso-ventral compression. The head is very 

 small, broader in front than behind, with prominent eyes, each with 

 three or four bright red spots. The antennae are very short, nearly 

 equal in length, the upper pair with eight joints in the flagellurn, 

 the lower with six. In the female the first and the seventh 

 segments of the thorax are the shortest, the former being not 

 much larger than the head : the second, third, fourth and fifth 

 are nearly equal in length, the sixth rather shorter. In breadth 

 the segments gradually increase frorn before backwards, the first 



