164 Messrs. Alder and Hancock on a new Genus 



placed posteriorly. These lateral rows are united anteriorly by 

 four large elliptical tuberculated papillae, passing round the head 

 in front of the dorsal tentacula on the same line with the branchise. 

 Five smaller ones alternate with these below. The foot is deeply 

 grooved in front and bilobed ; the sides rounded ; it tapers to 

 a fine point behind. 



A single perfect specimen of this very curious little animal was 

 obtained by dredging in shallow water at Malahide, near Dublin, 

 in September last, adhering to the common sponge [Halichondria 

 panicea), which is there found in very large masses. It turned 

 sickly soon after it was caught, and during the first night lost se- 

 veral of its larger appendages. It revived however afterwards, 

 and lived with us two or three weeks, during which time many 

 of the branchise were reproduced and grew very rapidly. The 

 papillae in front of the head, which were among the parts that had 

 fallen off, never re-appeared, but fortunately a sketch of them had 

 been taken when perfect. As they were observed not to contain 

 the central coloured vessel, they were probably not connected 

 with the gastro-vascular system. From not having examined 

 them under the microscope, we are unable to say whether or not 

 they performed the office of branchiae. On the papillae down the 

 sides, however, vibratile cilia were detected. 



At the same time wdth the above, the two following new species 

 of Eolis occurred. 



E. alba. — Body very slender, pellucid, white, with a faint tinge 

 of yellow from the viscera shining through. Dorsal tentacula 

 smooth, approximating at the base, dark brown and slightly 

 tapering for about two-thirds up, where there is a bulb or 

 button-like expansion, above which they are white and more 

 slender, terminating in a blunt point. Oral tentacula long, 

 white, tapering to a fine point. Branchice linear-oblong, opake 

 white, with a dark olive-coloured ring near the termination, 

 having another circle of opake white above it. They are set in 

 five or six distant clumps down the sides ; the opposite ones 

 approaching each other in the centre and having a ruff-like ap- 

 pearance. The first two clumps contain two rows of six or seven 

 papillae each ; the rest are in single series decreasing towards 

 the tail. Foot linear, pellucid, the anterior angles produced 

 into long, slender tentacular processes, terminating posteriorly 

 in a fine point. Length half an inch. 



This is an extremely graceful animal. Two specimens were 

 obtained. 



E. Farrani. — Body slender, transparent white, with a delicate 

 tinge of yellow ; a few spots of bright orange occur on the head 

 and back, and a streak of the same colour at the tail. Dorsal 



