[ 64 ] 



nearly filled the interior of the shell, the ends of the spires being 

 either directed outwardly towards the cardinal angles (Spinfer) 

 or placed horizontally with their apices directed inwards and 

 towards the centre of the concave surface of the same valve, which 

 they almost filled, the inner side of the spires were pressed together 

 and flattened with thin terminations close to each other, near the 

 centre of the bottom of the shell (Atrypo). In the Rbynchonellidaj 

 again it assumed the shape of two short slender curved lamina), 

 while in many genera, and even families, Productidoe, &c., there 

 existed no calcified support for the branchial appendages. 



SOFT PARTS OF ANIMAL. 



He must very briefly allude to the soft parts of the animal, 

 but it would require much more time than could be bestowed to 

 his short lecture, to do anything like justice to so difficult and 

 complicated a subject. He was, however, truly happy in being 

 able to inform the society that this important enquiiy had been 

 most ably and successfully elaborated during the last twenty 

 years, and by some of the most distinguisned anatomists of the 

 period. To such men as Owen, Huxley, Hancock. Gratiolet, Vogt, 

 Morse, and othei-s, we were indebted for an extensive series of the 

 most elaborate and accurate dissections and oljservations, which 

 had defined to a vei-y considerable extent, what were the true 

 characters of the Brachiopod, while some important researches 

 elaborated by Steenstrup, Lacage-Duthiers, Morse, Dr. Fritz 

 Mliller, Oscar Schmidt, McCrade, Kowalevsky, and others, had 

 thrown much additional light upon the embiyology, or early stages, 

 of the groups. Some differences of opinion, it was true, had been, 

 and were still, entertained with respect to the exact function to be 

 attributed to cei'tain parts of the animal ; but on all essential 

 questions there was a pretty general agreement. Before describing 

 the soft parts of the animal, it might be as well to mention that 

 Brachiopoda had been divided into two great groups by Bronn, 

 which he termed Apygia and Fleiiropygia, considering them to be 

 inadmissible on certain grounds. Professor King suljstituted the 

 name Clistenterata for the first group, on account of its including 

 animals destitute of an anal aperture; and the term Tretenteratu 

 for the second, as it embi-aced animals provided with this organ. 

 The former division contained species which had their valves 



