TUNICATA OF THE L.M.B.C. DISTRICT. 247 
dozen large specimens were dredged from twenty fathoms, 
about twenty miles 8.H. of the Isle of Man. In January, 
1888, a specimen was collected on the shore at Puffin 
Island. In the dredgings made from the “‘Hyena,” on 
May 20th, 1888, between the Calf and Port Erin, several 
specimens were obtained from a depth of twenty fathoms. 
Some of these were very transparent. 
A number of very large specimens were dredged in 
November, 1888, from a trawler, at about twenty miles 
north of Puffin Island, depth twenty fathoms. These last, 
and also the ‘‘ Weathercock”’ specimens obtained from the 
centre of the Irish Sea, are very fine, some of them 
extending to 8 cm. in length, and have a very powerful 
muscular system. The longitudinal muscle bands of the 
mantle are especially large, and the anterior ends of the 
specimens are more completely retracted than I have ever 
seen before, being invaginated to such an extent that a 
deep pit is formed, at the bottom of which are found two 
small pits formed by the branchial and atrial siphons 
having been turned completely outside in (see Pl. XIII., 
fig. 13). 
In some of the specimens the colour of the pigment 
has not been changed by the alcohol, and the ocelli are 
still bright red. One has a specimen of Saxicava rugosa 
partly imbedded in the test; the Mollusc usually found 
in Ascidians is Modiolaria marmorata. 
Many of these specimens might be referred to Roule’s 
sub-genus Plewrociona,* as they lie flat and are attached 
to large shells or other objects along the greater part of the 
* Roule, ‘‘Revision des espéces de Phallusiadées des Cotes de Provence,” 
Recueil Zoologique Suisse, t. ili., no. 2, p. 239, 1886. Roule describes a new 
species, Pleurociona edwardsi, which appears to differ little if at all from Ciona 
intestinalis. Besides the condition of attachment of the body, the membrane 
which separates the viscera from the peribranchial cavity is said in Pleurociona 
to be oblique in place of perpendicular to the longitudinal axis of the body. 
