ANATOMY OF AIJENICOI.A ASS1]\[TLIS. 757 



pouches, to the number of peven on each side, are present in 

 the three specimens examined. The anterior pair is lono- 

 and filiform or clnb-shapod, measuring- in one case 15 mm., 

 and in the other two specimens 24mm. in length. The other 

 pouches are pyriform or ovoid, and 3 to 5 mm. long". 



Vascular System. — The vascular system agrees closely 

 with that of A. marina,^ and only differs from that of A. 

 assimilis in the position of the first efferent branchial 

 vessel. The first six efferent branchial vessels open into the 

 subintestinal vessels, and the last seven into the dorsal 

 vessel. The heart of the specimen 120 mm. long contains a 

 moderately developed heart-body. 



Nephridia. — There are six pairs of nephridia, opening, as 

 in A. marina and A. assimilis, on the fourth to the ninth 

 segments. In the three specimens examined the first pair 

 is smaller than any of the others, and one of the nephridia is 

 considerably reduced, no funnel being visible. The funnels 

 of the first nephridia lie on the anterior face of the first dia- 

 phragm. Their dorsal lips bear about six broad, but usually 

 undivided, ciliated processes, and their ventral lips, thougli 

 small, are thrown into several of the peculiar folds or frills 

 as described above (p. 746) in the nephrostomes of A. 

 assimilis. The funnels of the other nephridia are larger ; 

 their dorsal lips bear about sixteen spatulate processes, most 

 of which are subdivided terminally into five or six, and their 

 ventral lips are thrown into some twenty or more folds. The 

 vesicles of the nephridia had been recently greatly distended 

 but are now almost empty. 



Gonads. — The gonads are small and occur in the usual 

 position. None are present on the first pair of nephridia. 

 It is probable that the breeding season of these specimens 

 was practically over at the time of their capture (September, 

 1899). It is evident that the nephridial vesicles had been 

 recently subjected to great distension, and this was probably 

 due to the accumulation therein of genital products. Similar 



' Except that in the ()t,a[:fo specimens llicre is in connection willi tlie tliiid 

 neplu'ldiuiu only one blood-vessel, viz. an allerent branch of the ventral vessel. 



