SPONGES COI,LECTED IN SCOTLAND. 249 



Ireland. Hanitsch's specimens, like my own, were devoid of gemmules ; 

 but I think there can be little doubt that his identification is correct. 

 My specimens were found on the lower surface of stones at the edge of 

 Loch Baa, together with the peculiar form of Spongilla lacustris described 

 above, and with specimens of the Polyzoon Frede^'icella sultana, some of which 

 were enclosed in the substance of the sponge as far as the base of the 

 colony was concerned, but were not perceptibly modified thereby. 



The sponges were in the form of rather thin crusts with a circular 

 or oval outline and not more than about 3 cm. in diameter. The surface 

 was raised at one or more points into conical eminences resembling- 

 volcanoes in miniature, on the summit of which the oscula opened ; 

 numerous furrows beneath the dermal membrane radiated from each 

 osculum. The mass was moderately soft, although the spicules were 

 abundant, the skeleton being incoherent ; the spicules were sharply and 

 rather abruptly pointed, measuring on thejaverage 0*201 by 0'0125 mm. ; 

 the shafts were densely covered with short, sharp, straight spines, but 

 the points were smooth ; no blunt spicules or developing rotules were 

 seen. Numerous embryos were present in the substance of the sponge. 



The identification of a specimen devoid of gemmules is always a little 

 uncertain in the Spongillinse ; but the spicules of Tuhello. pennsylvanica, 

 although several forms of the species have been described as varieties,. 

 have a very characteristic appearance, and the external and skeleton 

 characters of my specimens accord well with Potts's description. 



Tiibella pennsylvanica was one of the three North American forms 

 recorded by Hanitsch (ojj. cit?) from the West of Ireland in 1895, and 

 regarded by him, and later by Scharff * , as evidence of a faunistic connection 

 between that district and America. Of one of these species, however, I 

 have found, both in Calcutta and in the Western Ghats (Bombay Presidency), 

 a very close ally, which may ultimately have to be considered as no more 

 than a local race, namely Ephydatia indica f, which is possibly a form, of 

 the North American E. crateriformis, with which Hanitsch, I think rightly, 

 associated an immature sponge in his Irish collection |. Moreover, 

 Trochosponf/illa latoucMana, only known from Calcutta, bears much the 

 same relation to T. leidyi, another North American species which has 

 not as yet been recorded from Europe. The retiring habits and small 

 size of Tid)ella pennsylvanica render it liable to be overlooked, and I have 



* ' European Animals,' p. 34, 1907. 



t Annandale, Journ. Asiat. Soc. Bengal, 1907, p. 21, and ' Records of the Indian 

 Museum,' i. p. 272, 1907. 



X The distribution of the third form in Hanitsch's Irish collection {TLeteroraeyenia 

 ryderi) is apparently discussed by Miss J. Stephens Q Irish Naturalist,' 1905) in a paper 

 I have not seen. 



