522 PROCEEDINGS OF THE ACADEMY OF [Sept., 



A single depressed, more widely umbilicate Ptychocochlis was found 

 on the ridge near Lincoln. It probably represents another species. 



ERICIIDJB (CYCLOSTOMATIDiE;). 



The Jamaican Cyclostomas differ from Ericia clcgans of Europe by 

 the form of the muzzle, which is deeply bifid at the end, not flattened 

 and disk-like clistally, as Fischer figures that of E. elegans. In creeping 

 the muzzle takes no part, and is not applied to the ground except occa- 

 sionally for the purpose of feeling. The foot is divided lengthwise by a 

 median sulcus, only the two outer edges being in contact with the earth 

 in crawling, which is effected by the passage of high narrow folds or 

 waves from the tail forward alternately on the two sides, only one at 

 a time on a side. The wave lifts free from the support, as shown in 

 fig. 3, so that there is no sliding motion of the sole against the ground. 

 Viewed from in front or behind the snail has an absurd appearance 

 of striding along on stumpy legs. These observations were made on 

 Colobostylus jayanus rufilabris (Ad.) and Tudora arrnata (Ad.) 5 . 



<Lr 





Fig. 3. — Colobostylus jayanus rufilabris (Ad.). Fig. 4. — Head of same, from above. 



Colobostylus jayanus (C. B. Ad.). 



Roadside north of Alandeville; ridge near Lincoln; Somerset. 

 Colobostylus jayanus rufilabris C. B. Ad. Figs. 3, 4. 



Kendal road, 2 miles north of Mandeville, on stone walls; Benmore, 

 Mandeville ; woods at King^Edward's Hotel; Somerset road, 2 miles 

 northwest of Mandeville. 



5 It may be of interest in this connection to quote Dr. Jousseaume's account 

 of the walking of Ericia elegans. The foot is divided by a median line or raphe. 

 "Pour avancer, Panimal glisse en avant l'une des moities artificielles de son 

 pied et lorsqu'elle a depasse Pautre du quart, plus au moins, de son longueur, 

 elle s'arrete, pendant que l'autre moitie sort de son immobility et s'avance a 

 son tour, depasse sa congenere que se remet alors en mouvement. Cette progres- 

 sion alternative se fait sans interruption ; elle est continue comme dans les 

 autres modes. Qu'on suppose un homme, les deux pieds dans un sac, avancant 

 en glissant le pied droit, puis le pied gauche et ainsi de suite successivement 

 et l'on aura une idee exacte de la progression d'un Cyclostome" (Bull. Soc. 

 Zool. France, Vol. 34, 1909, p. 113). 



