490 MK. JAMES RITCHIE ON HYDROIDS [May 28, 



Family Seetulakiidjj. 



Sertularia distans Lamx. 1816. 

 „ mai/eri Nutting 1904. 



„ versluysi Nutting 1904. 



„ leevimarginata, sp. n. 



Familj'^ Plfmuiariidj?. 



Fliumilaria Jialecioides Alder 1859. 

 MonostcBchas quadridens (McCradj- ]8o7). 

 Aglaophenia marginata, sp. n. 

 Lytocarpus grandis, var. unilateralis, var. n. 

 „ crosslandi, sp. n. 



Of the 18 hitherto known forms above mentioned, 10 are recog- 

 nised as British species, while 5 of the remainder {Catnpamdaria 

 2)tijchoGyathzis, Sertularia mayeri, S. verslitysi, Lytocarpus grandis, 

 MonostcBchas quadridens) are, with the exception of the last 

 which has been recorded from the Indian Ocean (Tliornely, 1904), 

 distinctively American. This contingent is probably to be ac- 

 counted for by the oceanic whirlpool the centre of which is marked 

 by the Sargasso Sea and the streams of which wash the shores of 

 the West Indies, of eastern Mexico, and of the eastern United 

 States, and, circling in the North Atlantic, sweep past the 

 Azores, Madeira, and the Cape Verde Islands. 



The collection, as might be expected in a littoral one, is com- 

 paratively rich in gymnoblastic forms and includes an interesting- 

 species, peculiar in branching and in gonophore, which has been 

 made the type of a new genus, tSolenio-psis. 



We note also, as Pictet has already remarked (Pictet, 1893), 

 that of those species which occur both in temperate and in tropical 

 waters, the individuals existing in the colder seas are, in general, 

 larger and more sturdy than their tropical specific equivalents. 



The outlines of the figures, both in the plates and in the text, 

 with the exception of those representing the appearance of the 

 specimens to the unaided eye, were drawn with the helji of Zeiss's 

 camera lucida. 



The localities from which Mr. Crossland obtained his specimens 

 are shown below : — 



ST. VINCENT, Cape Verde Islands. 

 (1) General. 



(a) From tidal pool, 25th July, 1904. 



Fennaria cavolinii Ehr. 

 (6) 2 fathoms, among coral, 22nd July, 1904. 



Fennaria cavolinii Ehr. 



Sertularia mai/eri Nutt. 



Flumularia Jialecioides Hiucks. 

 (c) 10 fathoms, 27th July, 1904. 



GonotliyreBa gracilis Sars. 



Campanularia ptycliocyatlms Allm. 

 (fZ) 15 fathoms, 30th July, 1904. 



MoHosteeclias quadridens (McCrady). 



Lytocarpus grandis, var. unilateralis, var. n. 



