394 ON THE LIFE-HISTOET OF CERTAIN ACABINA. 



segmentation very clearly. Rostrum oblong, almost square, hardly 

 seen from above, being much folded down on the ventral surface ; 

 it is also very retractile, capable of being almost entirely w^ith- 

 drawn into the camerostomum ; it bears two pairs of short setae, 

 but these do not spring from a tube as in Hypopus. There are 

 a few smaller hairs. The dorsum is nearly covered by three 

 transparent chitinous plates, slightly imbricated ; they do not 

 reach the lateral margin, and are rounded towards it. The first 

 plate bears two pairs of large serrated spines slightly curved ; 

 each of the other plates bears one pair. There are two smaller 

 similar plates on each side, each plate bearing a similar spine. 

 Beyond these plates the margin is membranous ; this part is 

 wide posteriorly, and divided into large lobes all round. The 

 posterior termination of the abdomen is a retractile lobe or seg- 

 ment, bearing two pairs of very long curved spines, of unequal 

 length, the shorter being the thicker and most strongly serrated. 



The legs are about half the length of the body, approaching 

 conical, almost straight ; coxae thick; joints gradually diminishing ; 

 tarsi slightly curved when seen from the side ; from that view 

 they end very bluntly, and all three pairs are terminated by a 

 strong didactyle claw on a slender peduncle. Two very long 

 flexible setae are inserted near the distal end of the first tarsus, 

 shorter ones on the other legs ; all the joints have several shorter 

 spines. The creature is very mobile, and can lengthen and shorten 

 its form considerably. 



The egg is almost globular, milky -white, and witbout any con- 

 spicuous markings. 



DESCEIPTION OF PLATE XV. 



DiSPARIPES BOMBI. 



Fig. 1. Larva. Dorsal view, X 400. 



2. Adult male. Dorsal view, X 200. 



3. Adult female. Dorsal view, X 150. 



4. Adult female. Ventral view, X 150. 



6. Tarsus of first leg of male, side view, X 600. 



6. First leg of adult female, X 800. 



7. Claw of same leg (from within). 



8. Ungues and caruncle of second leg of adult female. 



9. Fourth leg of adult female, X 500. 



