ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 491 



again by mechanical and light-stimuli. There must be connections 

 between the integumentary nerve-cells and the ganglia in the pedal 

 nerve-network. (3) In pieces of Arion mechanical stimuli induced 

 energetic contraction, while luminous stimuli induced the wave-play. 

 (4) Pieces of Limax showed stronger " waves " than pieces of Arion • 

 as Simroth showed, the pedal nerve-network in the former has many 

 transverse commissures which do not occur in the latter. (5) Median 

 pieces have less power of movement than the head- and tail-pieces. 

 (6) Fragments of head- and tail-pieces can move even more quickly 

 than intact animals. (7) Young specimens of Limax move more 

 quickly than the adults. 



Entosiphon Deimatis Parasitic in an Abyssal Holothuroid.* — 

 E. Koehler and C. Vaney found this new parasite in Deima MaJcei 

 Theel. They describe the structure which resembles in many ways 

 that of Entocolax, two important differences being the retention in 

 Entosiphon of a spirally twisted visceral mass and of a relatively com- 

 plex nervous system. Moreover, while Entocolax is known only as 

 female, Entosiphon is hermaphrodite like Entoconcha. And Ento- 

 siphon has more intimate parasitic relations with its host than Ento- 

 colax has. 



The new form should be placed along with Mucronalia and Stylifer, 

 and probably Entocolax, in the family Eulimidse. Here also the author 

 would place Entoconcha. Some attention is paid to the " pseudo- 

 pallium," which seems to be a cephalic expansion on the upper region 

 of the proboscis. 



Structure of Pontiothauma.f — S. Pace gives a partial description 

 of P. mirabile E. A. Smith and P. abyssicola E. A. Smith, of which 

 only the type-specimens are known. It seems that the affinities of 

 Pontiothauma are with the Mangiliinge, and that its nearest allies are 

 Pleurotomella Verrill and Spergo Dall. 



Memoir on the Limpet.^ — J. P. Ainsworth Davis and H. J. Fleure 

 have written the tenth memoir of the Liverpool Marine Biology Com- 

 mittee's useful series. The subject is the common limpet {Patella 

 vulgata) and the chief objects of the memoir are to provide a reliable 

 account of the structure of this Gastropod, and to show the place which 

 it occupies in the class to which it belongs. 



The matter which the authors believe to be new includes the follow- 

 ing chief points : — (1) a lateral glandular streak has been found along 

 each side of the foot of young specimens, resembling that found in 

 Nacella and its allies ; (2) a muscular zone, named " the internal pallial 

 muscle," has been found extending in. the mantle between the tips of 

 the shell-muscle ; (3) the structure of the crop and inferences drawn 

 therefrom as to the special torsion of the viscera of Docoglossa during 

 consolidation of the visceral hump ; (4) the respiratory function of the 

 nuchal cavity as regards damp air ; (5) discussion of the evolution of 

 the present topographical relations of rectum, kidneys, pericardium, and 



* Rev. Suisse Zool., xi. (1903) pp. 23-41 (1 pi.). 



t Journ. Linn. Soc. (Zool.). xxviii. (1903) pp. 455-02 (1 pi.). 



J L. M. B. C. Memoirs, x. (1903) 76 pp. (4 pis.). 



