212 MISS J. DONALD ON IHE GENUS [May 1895, 



given by Prof. Haughton. 1 His type (C. telescojrium) is a shell 

 characterized by its large conical form, smooth, flattened, and but 

 slightly convex whorls, band not raised above the surface, base flat 

 and grooved, and mouth probably subrhomboidal. The structure of 

 the mouth and base distinguishes it from Ccelocaulus. 



"We have also another group which resembles the typical Mur- 

 cliisonice in having the band on the more prominent part of the 

 whorl, but which differs in having the band bounded by grooves 

 instead of keels, and in the whorls being more convex. It is 

 distinguished from Hormotoma by having the whorls ornamented 

 by bands or threads instead of being smooth, and the mouth is 

 oblong. This section might be called Glyphodeta, with M. zonata, 

 Don., for the type. 



I must here refer to a new subgenus of elongated shells from the 

 Trias of St. Cassian, which Koken 2 calls Cheilotoma. He considers it 

 to be more allied to the Alariidae and Cerithiidse, with some charac- 

 teristics of the oldest Loxonema, than to Murchisonia ; but Kittl 3 

 classes it as a subgenus of the latter genus. It has a sinus in the 

 outer lip which is represented on the whorls by an excavated band 

 bounded by keels : this band is situated above the angle on the 

 lower whorls. Koken states that C. amtum has the mouth widened 

 and extended on the spire. According to Kittl, C. Bhimi also 

 possesses this peculiarity, and he does not attach much importance 

 to it, but considers it a late acquisition. Koken represents the 

 mouth with an anterior canal bent backwards, whereas the figures 

 of Kittl only show such a canal as belongs to the true Murchisonia?. 

 The specimens of M. Blumi in the British Museum (Natural History) 

 have a decided canal bent backwards, but not so much as in the 

 figure of M. acutum of Koken ; they also indicate the spreading of 

 the lip on the spire. 



Genera intermediate between Murchisonia and 

 Pleurotomaria. 



Besides the above divisions of the elongated shells referred to Mur- 

 chisonia, I must notice four which appear to be intermediate between 

 Murchisonia and Pleurotomaria, namely, Lophospira, Worthenia, 

 Pithodea, and Oaliendrum. The first genus was established by Whit- 

 field * for shells whose angular whorls are very closely coiled round 

 the axis, so that the upper whorls are more exsert than usual, the 

 sinus is of greater or less depth, but not necessarily a slit like that 

 of Murchisonia or Pleurotomaria, the lower whorls have a tendency 

 to become disconnected in the advanced stages of growth, and the 

 columella is always minutely perforated. The second genus was 



1 ' On some Foss. Pyramidellidse from tbe Carb. Lste. of Cork and Clonmel,' 

 Pi-oe. Dublin Univ. Zool. & Dot. Assoc, vol. i. pi. iii. p. 282, pi. xx. figs. 2-4. 



2 ' Ueber die Entwiekelung der Gasteropoden vom Cambrium bis zur Trias,' 

 JNeues Jabrb. Beilage-Bd. vi. (1889) p. 455. 



3 ' Die Gastropoden der Schichten von St. Cassian der Sudalpinen Trias/ 

 pt. i. Annal. k.-k. naturbistor. Hofnius. vol. vi. (1891) p. 218. 



4 Bull. Amer. Mus. Nat. Hist. vol. i. no. 8 (1886), p. 311. 



