Mr. W. H. liensou 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 in 

 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. 

 Fig. 2 a. A. polype in a state of contraction. 



Plate VIIL 

 Fig. 3. The free zooid of Clavatella prolifera. 



Fig. 4. Eleutheria dichotoma '] rj? j. ■ er, f\ j. r y n n 



4 a. The ovary J L"°™ ^ tracing of De Quatrefages s figure.] 



Fig. a. The sexual bud of Clavatella as it appears at first. 



Figs, b 81 c. The same, in more advanced states. 



Figs. d&.e. The bifurcate arm of the zooid in the early stages of development. 



Fig.f. The same, full grown. 



Fig. g. A portion of one of the arms. 



Fig. h. A thread-cell. 



Fig. 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 nonnuUis spiralibus obso- 

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

 mide decidua albida, apicem versus rubente, infra peripheriam 

 fascia lata cserulescenti-nigro-castanea margine peripherico satu- 

 rate castaneo ornata ; epidermide superne fusco-cornea, subtus 

 viridescente, umbilicum versus luteo-fulva ; spira convexiuscula 

 parum elevata, apice planulato, valde obtuso, sutura lineari, antice 

 parum impressa ; anfractibus 5, sensim accrescentibus, subplanu- 

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

 pheriam subcarinato, carina demum evanescente, subtus convexo, 

 antice subinflato, periomphalo prope marginem columellarem 

 compresso, subito excavate ; apertura obliqua, subovato-lunata, 



