70 ABNORMAL CONDITIONS OF THE LIMBS. 



immensely enlarged posterior fontanelle. The exoc- 

 cipitals are very large and perforated by a considerable 

 foramen. The spinal canal is open, the laminae and 

 spines being spread out on either side ; several are an- 

 kylosed together, as are also the three upper ribs of the 

 right side. The bodies of the cervical vertebrse exhibit two 

 lateral centres of ossification, a condition very constantly 

 met with in conjunction with other forms of abnormal 

 development. Mr. Langstaff's Museum. 



290. A male Human anencephalous foetus. 



Presented by John Abbey, Esq., 1826. 



291. A male Human anencephalous foetus with the placenta ad- 



herent to the membranes of the brain. 



Presented by T. M. Donohoo, Esq., 1862. 



292. A female Human anencephalous foetus with ectopia of the 



viscera. The sac containing the protruded intestine has 

 been laid open; a large portion of the placenta is seen ad- 

 hering to the sac. 



These two preparations are interesting, as they show an extremely 

 frequent complication of these conditions. On a priori grounds it 

 would appear extremely likely that the placenta would become 

 adherent to an open membranous surface like the peritoneum, 

 arachnoid, or pia mater, or to the edge of an ulcerating surface like 

 that exhibited by No. 282. It is not a little remarkable that so 

 many have considered such adhesion as the cause of the malfor- 

 mation, as it is far more probably an effect, or an accidental com- 

 plication extremely prone to occur. 



Hunterian. 



SERIES III. 



ABNOBMAL CONDITIONS OF THE LIMBS. 



I. IN INVERTEBRATES. 



293. A small Crab in which the upper nail of the left claw ex- 

 hibits the form of an entire claw, without, however, any 

 joint at its base. Purchased. 



