338 



through the cup splitting it in two, one half of which is shown in fig. 325, 

 b. It is evident that this specimen consists of only the upper extremity of 

 the fossil, and that the upper right hand sloping side of b, above, repre- 

 sents one-half of the margin. From the form of this part it might be 

 supposed, at first sight, that the fossil was obliquely terminated at the 

 upper end, one side of the cup being lower than the other. But it will 

 be observed that the narrow cylindrical cavity of the cup enters at a 

 right angle to the general plane of this sloping side, and that, half-way 

 down, it is curved so as to meet the lower straight side, also at a right 

 angle. This proves that the fossil, when perfect, was considerably curved. 



In the transverse section at a, is shown the diameter of the cup, five 

 lines. Its centre is seven lines from the exterior on the lower side of the 

 figure, which corresponds to the outer or convexly curved side of 

 figure b. But it is eighteen lines from the exterior of the opposite side. 

 Its position, thus, in this specimen, is very eccentiic. In the specimen 

 figured on p. 210, it is central. In the lower part of b, the structure of a 

 portion of the inner wall of the cup is shown. It is perforated by small 

 ovate or sub-quadrate pores, most probably the apertures of a system of 

 radiating canals. These pores are arranged in straight longitudinal rows, 

 and there are from three to four pores in the length of two lines in each 

 row. There are four rows in the width of two lines. In the transverse 

 section, a, the course of the canals radiating from the centre outwards is 

 shown. The whole fossil appears to be composed of a number of concen- 

 tric laminae from one-fourth of a line to one line in thickness. Each of 

 these is no doubt a repetition of the inner wall of the cup, and they are 

 all perforated by the radiating canals. Between the concentric layers, 

 another set of canals ascends from the base upwards, and it is probable 

 that all communicate with each other, vertically, laterally, and in a radial 

 direction. I cannot determine from these specimens whether or not this 

 species had an external layer of a spongy texture, as seems to have been 

 the case with C. pannosutn. 



Judging from the form of what remains of it, this specimen must have 

 been 5 or 6 inches in length when perfect. It was found in division H, 

 Pistolet Bay, Newfoundland, along with the specimen figured on p. 210. 



I have referred it to C. Anstedi with doubt, because its structure 

 seems to be somewhat different, being more compact towards the exterior. 

 Should it turn out to be a distinct species, I propose to call it Calathium 

 crassum. 



