BIOLOGICAL RESULTS OF THE "ARGO" CRUISE. 209 



dorsally so as to make a narrow loop and reach the anterior 

 edge of the stomach. It then turns anteriorly and runs 

 parallel to the oesophagus as the rectum which ends 

 behind the middle of the branchial sac in an anus, the 

 margin of which is cleft into 14 finger-like processes 

 (PI. IX., fig. 3). The usual delicate branched gland is 

 found ramifying over the surface of the intestine. 



Beproductive Organs were not found, but the mantle 

 has a number of endocarps projecting from its inner sur- 

 face, so no doubt polycarps would be developed later on. 



The single specimen for which this species is formed 

 was dredged with a large number of specimens of Ascidi- 

 ella aspersa in Killary Lough. 



This species comes near to Heller's Polycarpa gracilis * 

 but differs from it in the more anterior position of the 

 atrial aperture, the less prominent folds in the branchial 

 sac, the very narrow dorsal lamina, the fringed anus, the 

 shape of the stomach, and the course of the intestine. 

 Ascidiella aspersa, 0. F. M., var. pustulosa, A. & H. (PI. X.) 



In Killybegs harbour the dredge brought up from a 

 muddy bottom great numbers of a large ascidian, which 

 corresponds exactly with Alder and Hancock's description 

 of Ascidia pustulosa, but that species is undoubtedly 

 merely a large and rough form of Ascidia aspersa, and so 

 pustulosa cannot be regarded as more than a variety. 

 Miss Warham has examined, under my supervision, all 

 the specimens preserved, with the object of finding para- 

 sitic copepoda, and has come upon a few abnormalities, 

 which are noted below. The copepoda were submitted to 

 Mr. I. C. Thompson, who has kindly identified them. 



Out of 26 large specimens taken by chance from one 

 store bottle, 21 contained copepoda, and one had a small 



*Denkschr. d. K. Akacl. d. Wissensch., Wien, Bd. XXXVII., p. 262, 

 1877. 



