Mr. C. Collingwood on Nudibranchiate Mollusca. 467 



ia the Mersey are usually of a fine brick-red colour and about 

 an inch long; but at Leasowe, about two miles from its mouth, 

 Dr. Edwards and myself have found them fully an inch and a 

 half long, but of a paler colour. These large specimens much 

 resemble E. papillosa in aspect, and are scarcely so handsome as 

 the smaller ones. Indeed, in the Nudibranchiate family, we 

 might almost say that size and beauty are in inverse proportion 

 to one another ; under a low magnifying power the minuter spe- 

 cies exhibit delicacy of tint and texture far outri vailing those 

 which do not require a glass for their examination. The Eolis 

 Drummondi is one of the most active of the genus, constantly 

 walking about, waving its long and most graceful tentacles, or 

 swimming on the surface, and when disturbed, erecting by a 

 sudden movement all the papillse upon its back, "like quills 

 upon the fretful porcupine.'^ The papillse of this and some 

 other species, especially of E. picta, often fall off when the ani- 

 mal is about to die; and I have observed, in the case of E. 

 Drummondi, a persistent vitality in the separated parts. For 

 some time after they have fallen, the papillse exhibit a vermicular 

 motion, which, when examined under the microscope, is seen to 

 be a general contraction, independent of any artificial stimulus. 

 Eolis Landsburgii. — It is gratifying to me to be able to record 

 the estuary of the Mersey as a new locality for this exquisite 

 little Nudibranch. As Dr. Edwards and myself were examining 

 the Egremont shore at the beginning of the present month, the 

 former picked up a specimen of the above Eolis. The very rich 

 amethystine colour of the body at once referred it to the species 

 Landsburgii ; but on comparing it with the figure given by Alder 

 and Hancock, we were a little puzzled by certain discrepancies. 

 In the first place, the colour both of the body and papillse was 

 very much deeper and richer in our specimen than in the plate ; 

 that, however, was of minor importance. Secondly, the papillse 

 were much more numerous, as well as longer and more elegantly 

 formed, than were those of the specimen figured ; but on refer- 

 ring to their Appendix, the authors tell us that their figure was 

 taken from an immature individual, the only one then known. 

 The most striking difference, however, was in the tentacles. 

 The specimen figured has the dorsal tentacles rather long, 

 slender, and linear, and the oral tentacles a little longer than 

 the dorsal; but in our specimen the oral tentacles were very 

 short and thick, with transverse wavy markings, while the dor- 

 sal were nearly three times as long, arched forward, and pre- 

 senting an outline not unlike an ibex-horn. This gave the 

 animal so different an appearance that, having watched it for 

 some hours and finding no change, I began to think it might be 

 a new species ; and as it seemed to be getting less lively, I made 



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