154 REPORT — 1861. 



A^ertebra. The posterior paii; of the pleiu'apophysis of the fourth cervical of the mole 

 is further interlocked between the pleiu'apophysis of the fifth cerAical below, and 

 the anterior zygapophysis of the same vertebra above. The pleurapophysis of tlie 

 fifth cervical resembles that of the fourth. In the sixth cervical it is much more 

 developed, both forwards, backwards, and downwards, the pair forming the sides 

 of a deep and wide channel on the under part of that vertebra. In the seventh 

 cervical the plexu-apophysis is not developed ; the diapophysis forms a small obtuse 

 prominence below the anterior zygapophysis, and, in the ordinary language of 

 anatomy, its " transverse process " would be said to be "imperforate." With re- 

 gard to the common description of the cervical vertebra} of the mole as mere rings 

 of bone, the term is applicable only to the neural arclies of the five last vertebrnc, 

 none of which have a spine, except the third and seventh, and in these it appears 

 as a mere tubercidar beginning. The bodies of the vertebrre are subdepressed, but 

 otlierwise are well-developed quadi-ate bones, closely united, so as to concur with 

 the peculiar size, shape, and arrangement of the "transverse processes" above de- 

 scribed, to give strength to the neck and impede any lateral inflexions. It is easy 

 to show on a recent mole, when the cervical vertebi'as are exposed by removal of 

 the enormous masses of muscles with which they are surroimded, that the lateral 

 inflexions of the neck are confined to movements between the atlas and dentata, the 

 dcntata and the third vertebra, and between the sixth and seventh vertebra}, but 

 are as effectually impeded in the intervening vertebrfo as in the crocodile itself 

 Nor is the movement upwards and downwards between the same vertebrae of more 

 than a limited extent. The osseous style developed in the lif/amcntmii nucluc, co- 

 extensive with the cervical series, and rimning parallel with the course of their 

 undeveloped spines, stiffens the neck in respect of its vertical inflexions beyond the 

 atlas, as well as augments the lever power of tlie muscles which raise the head. If 

 the service to the mole of a stifl' neck in the fossorial applications of the snout and 

 head had been called to mind, the analogy of the more efficient modification to 

 that end in the bun-owing annadiUos, might have led to an examination of the 

 actual structure of this part of the slceleton of the mole, which would have ren- 

 dered xmnecessary the present communication on the subject. 



One of the objects Professor Owen had in view in troubling the Section with 

 what some might deem too trifling a matter, was to encourage younger compara- 

 tive anatomists to exercise their skill on indigenous sidjjects which may any day be 

 brought within their reach. Their organization is far fj-om being exhausted by 

 direct and original scrutiny, and the highest generalizations in comparative anatomy 

 might be tested and illustrated by the anatomy of our commonest fishes, reptiles, 

 birds, and mammals, independently of raiities from foreign shores. 



In conclusion, he might fiu'ther state respecting the mole, that its loins were 

 streng-thened by superadditions to their vertebras, precisely like those discovered 

 by Sir Philip Egerton in the cer^ncal vertebras of tlie Ichthyosaurus, viz. by a series 

 of " subvertebral wedge-bones " inserted into the inferior interspace between oacli 

 of the six lumbar vertebras, as well as between tlie first lumbar and last dorsal, and 

 between the last lumbar and tlie first sacral. Tlicse, which Professor Owen liad 

 determined to be "autogenous hypapophyses," have their broad, rhomboidal, smootli 

 and sliglitly convex base downwards, and their narrower end wedged upwards into 

 the lower part of the intei-vertebral substance. It is obvious that the lumbar re- 

 gion, cooperating with the pelvis, as the fidcrum during the vigorous actions of the 

 hind feet by which the loose earth is kicked out of the bm-row, must derive an 

 advantage from this superaddition to their fixation, analogous to that wliicli tlio 

 Ichthyosaunis derived from the wedge-bones of its cervical vei-tebra3. The lumbar 

 h^-papophyses of tlie mole had not escaped the notice of the shai-p-sighted Jacobs, 

 who speaks of them as " ossicula sesamoidea " (loc. eit. p. 17) ; but he deduces no 

 physiological consequence from the fact ; and his passing notice of the structure 

 had not been recognized by any subsequent wi-iter on the osteology of the Insec- 

 tivora. From no systematic work or monograph on comparative anatomy, indeed, 

 could the student acquire any hint of so curious a fact that the vertebral column 

 of the mole combined two peculiarities which are separately given in the reptilian 

 class, inz. to the Crocodilia and the Enaliosauiia respectively. This paper was 

 illustrated by diagrams of the structures described. 



