908 DK. 3. RENNIE AND MR. H. WISEMAN ON THE [Dec. 11, 



Family DisTOMiDiE Giard, 1872. 



DiSTOMA CAPSULATUM Yaii ISTame. (Plate LXV. fig. 21.) 



The colony is incinisting, more or less lobecl, light brown or 

 greyish in colour, permeated with amorphous calcareous particles. 

 Size 25 mm. by 14 mm. and about 5 mm. in thickness. 



The test is semi-cartilaginous, no systems are apparent, and the 

 zooids are relatively few in number. 



The ascidiozooids (fig. 21) are elongated antero-posteriorly and 

 divided into a short branchial and a long abdominal region. The 

 branchial region measures 1'25 mm. and the abdominal is more 

 than twice as long. 



The mantle is highly muscular. The muscles are arranged in 

 well-defined longitudinal and transverse bands on the surface of 

 the pharynx. 



The branchial sac is short, and the branchial aperture is 6-lobed. 

 This aperture is apparently capable of being everted. The 

 endostyle is large and undulating. In the young forms the 

 separation between branchial and abdominal regions is not cleai'ly 

 marked. 



The atrial aperture, placed a short distance behind the branchial, 

 is also 6-lobed. 



The tentacles are simple and fairly numei'ous. 



Vascular processes arise from the posterior end of the abdomen. 

 The hepatic glands surrounding the intestine consist of numerous 

 tubules on the a,nterior portion of the intestine. 



Only a small colony was found, and it is doubtfully placed in 

 this species. The characters made out agree well with Van 

 Name's descrij)tion of the type, although some points remain 

 unverified for lack of satisfactory material. 



Previously recorded from Bermuda below extreme low- water 

 mark. 



Family Polystyelid^ Plei-dman, 1886. 



Synstyela incrustans Herdm. (Plate LXV. fig. 22.) 



Two colonies referred to this species came under observation. 

 One of these spreads over Styela cormgata, covering about 

 6 sq. cms. of surface and varying in thickness from 1 to 2 mm. 

 The other colony was attached to the tube of a Sabellid worm in an 

 investing mass of about 3 sq. cms. Slight difl:erences in external 

 appearance occur in both these colonies. The mass which covered 

 the simple ascidian was tough in texture arid dirty white in colour. 

 The zooids did not project above the common surface of the colony ; 

 they are oval, and in length measure 2*5 mm., in breadth 1*5 mm. 

 A distinct bluish tinge is noticeable in those zooids which cover 

 the tube of the Sabellid worm. Each zooid is slightly elevated, 

 and there is a more distinct sejDaration between each animal thaii 

 in the first mentioned colony. The size of each individual is 

 about 6-7 mm. in leneth and 2-3 mm. broad. 



