INIr. W. H. Benson on new Species of Helix. 81 



ductive body, and the variations are not such as to mask it. 

 We should rather bring the sexual buds of Clavatella into com- 

 parison with the Hydra than with the complex Medusiform zooids 

 of other Hydrozoa. 



One other peculiarity remains to be noted — the position iu 

 which the generative elements are produced. They occupy, as 

 I have mentioned, the extreme proximal portion of the body, 

 and apparently are most intimately connected with the ectoderm. 

 But further information is needed respecting the details of their 

 early development, and the precise nature of the cavity in which 

 they are included, which it will be my endeavour and hope to 

 supply hereafter. 



EXPLANATION OF THE PLATES. 



Plate VIL 



Figs. 1 & 2. Clavatella prolifera, natural size and magnified. 

 Fi(/. 2 a. A polype in a state of contraction. 



Plate VIH. 



Fiff. 3. The free zooid of Clavatella prolifera. 



Fig. 4. Eleutheria dichotoma "Irn .. c t^ n^ ^ r j^. n 



4 a. The ovary J '^"'^^^^ ^ tracnig of De Quatrefages s hgure.J 



Fiff. a. The sexual bud of Clavatella as it ajjpears at first. 



Fiffs. b 8c c. The same, in more advanced states. 



Fiffs. dSie. The bifurcate arm of the zooid in the early stages of development. 



Fiff.f. The same, full grown. 



Fiff. ff. A portion of one of the arms. 



Fiff. h. A thread-cell. 



Fiff. i. A young polype. 



XI. — Characters of a gigantic Helix from Southern India, and 

 of other Species from Northern India, the Malayan Coast, and 

 the Andaman Islands. By W. H. Benson, Esq. 



Helix Basileus, Bens., n. sp. 



H. testa subanguste umbilicata, orbiculato-subconvexa, irregulariter 

 striatula, prope suturam plicatula, sulcis nonuuUis spiralibus obso- 

 letis, subtus confertioribus, rugisque obliquis sculpta, sub epider- 

 mide decidua albida, apicem versus rubente, infra peripheriam 

 fascia lata c?erulescenti-nigro-castanea margine peripherico satu- 

 rate eastaneo ornata ; epidermide superne fusco-cornea, subtus 

 viridescente, umbilicum versus luteo-fulva ; spira convexiuscula 

 parum elevata, apice planulato, valde obtuse, sutura lineari, autice 

 parum impressa ; aufractibus 5, seiisim accrescentibus, subplanu- 

 latis, ultimo antice dilatato, depresso, non descendente, ad jieri- 

 pberiani subcarinato, carina denium evanescente, subtus convexo, 

 autice subinflato, j)eriouij)halo prope marginem coluniellarcm 

 conipresso, subito excavate ; apertura obHqua, subo\ ato-lunata, 



