in the West of Ireland. 357 



keel, to which the spines are fixed. The number of these 

 reaches twelve ; on the first ray-segment there are but two, 

 on the following three, on the next four, and so on, until, on 

 the tenth segment there are ten or eleven, and further on 

 twelve ; on the distal half the number decreases gradually to- 

 wards the point. All these side-spines are smooth, somewhat 

 compressed or flat, narrower at the root than at the obtuse 

 rounded extremity. They are all nearly of a size, except the 

 two or three lowest, which gradually become larger, so that 

 the lowest is the longest, nearly double as long as the upper- 

 most, or about as long as half the breadth of the ray. 



" On the lower surface of the ray, immediately within or on 

 the near side of the tentacle-pores (therefore not in a line with 

 the lateral spines) are two foot-papilla? : these are of a quite 

 unusual form, not being squamous, but spinous or cylindrical, 

 with pointed ends ; the outermost are very small ; the inner, 

 which are four or five times as long, or nearly as long as the 

 lateral spines, but much more slender, have their apices directed 

 forwards and inwards, so that they cross those of the corre- 

 sponding papillae of the opposite side. 



" Diameter of the disk 11 millimetres, length of rays 60 

 millims. Colour of the upperside of the disk chestnut-brown, 

 with large white rings, of which some are circular, some ellip- 

 tical or elongated, and others forming coalescent rings like the 

 figure 8 ; sides of the disk whitish, with small round chestnut- 

 brown spots ; ventral surface whitish. Rays chestnut on the 

 upper surface, with narrow white cross stria? ; spines greyish 

 brown. 



" This new Ophiuridan approaches, by its smooth disk, to 

 Forbes's genus Ophiopsila, but differs essentially in the ab- 

 sence of ray-plates and the presence of smooth papilla?. From 

 Ophiarthrum, Peters, which also has a smooth disk, it is sepa- 

 rated by its smooth ray-spines, which in that genus are spinu- 

 lose. From the genera Ophiomyxa and Ophioscolex, which 

 also have naked disks, it is separated by the absence of a 

 smooth integument on the rays. In respect of mouth-organs, 

 it stands nearest to Amphiura, Forbes, from which it differs in 

 its naked disk and spine-shaped foot-papilla?." 



Thyone fusus (Muller) and Synapta inhcerens (Miiller) were 

 found to be not uncommon in Birterbuy Bay in 12-14 fathoms; 

 the latter also occurred, in 4 fathoms water, in Clew Bay. In 

 Birterbuy Bay, Macrorhynchop>tertis granulosus (M'Coy) was 

 taken — and in Ardbear Bay*, on a very muddy bottom, several 



* Ardbear Bay, the bay on which the town of Clifden stands ; so named 

 in the maps of the Ordnance Survey. 



Ann. & Mag. N. Hist. Ser.4. Vol.m. 27 



