REPORT ON THE TUNICATA. 299 



A few small specimens of the species were also obtained 

 off Port Erin and Port St. Mary, Isle of Man, from depths of 

 ten to twenty fathoms. One of these, about 1*5 cm. in 

 length, had a Modiolaria, fully 5 mm. in length, living in 

 its branchial sac. 



Ascidia scabra, 0. F. Miiller. 

 Two specimens of this species, one of them rather large, 

 were dredged by Mr. Thompson, off Penmaenmawr, in July, 

 1885; and several specimens were obtained off Port Erin, 

 Isle of Man, in August. The larger specimen from Pen- 

 maenmawr has several small Modiolaria imbedded in its 

 test, and several of the Manx specimens are also infested 

 with this Mollusc. 



The branchial sac of this species seems particularly liable 

 to variation.* In some parts of the Penmaenmawr specimens 

 the internal longitudinal bars in place of being parallel to 

 the interstigmatic vessels, are inclined at a considerable 

 angle to them, consequently the stigmata cross the meshes 

 obliquely. There is a considerable amount of opaque white 

 pigmentation in the mantle, especially in the walls of the 

 very long branchial siphon. One of the Manx specimens 

 is most brilliantly marked with opaque white and scarlet. 



Ascidia elliptica, Alder and Hancock. 

 This species is recorded by Byerley as having been found 

 at Hilbre three or four times, attached to stones. No des- 

 cription of the species, except Alder and Hancock's account 

 of the external appearance,! has been published, and I have 

 not met with the species at Hilbre. Possibly it is the same 

 as Ascidia scabra. 



* See Herdmau, Journ. Linn. Soc, ZooL, vol. xv, pi. xvii, fig. 3. 



t Catalogue of Moll, of Northumb. and Dur., Trans. Tynes. Nat. F. C, 

 V. i, p. 107, 1848. 



