962 



TERATOLOGY. 



Fig. 619. 



The skeleton of the foregoing Aceplialus. 



a, mobile bone connected with the single cervical 

 vertebra. 



always twins, and not full grown. As far as 

 it has been mentioned by different obser- 

 vers, there is either a common placenta, with 

 two cords (Ponjol), or with one cord split 

 into two (Mery) ; or there are two placentae 

 connected together (Herhoklt); or there 

 are two totally separate ova, with a double 

 placenta (Moiiro). The external appear- 

 ance differs from that of the fourth type, by 

 greater length, and less truncated upper part 

 of the body, in which a feeble indication 

 of head may sometimes be visible (Ponjol, 

 Prochaska). The integuments are as in 

 the fourth type ; the toes are generally mal- 

 formed ; the arms and the external genital 

 organs are often abnormal. To the lumbar 

 part of the spinal column is joined an imper- 

 fect osseous thorax, sometimes with cervical 

 vertebras (Ilevermann), but without thoracic 

 viscera. The diaphragm exists in most cases. 

 There are vessels without a heart, which 

 cohere with the umbilical vessels. The viscera 

 of the epigastric region are commonly want- 

 ing ; Atkinson mentions only a liver. In some 

 intestines can be recognised either as intestina 

 tcnuia or crassa. The uropoietic organs, and 

 the internal parts of generation are commonly 

 pri'sent. There is in all a spinal marrow. 

 The observations as to the nervous system 

 are very incomplete. (Sec Jigs. 618, 619.) 



Sixth Type. Acephali ivith a trunk com- 

 posed of a thorax and an abdomen, and with two 

 superior and two inferior limbs. When the 

 trunk is more developed, the thorax becomes 

 more convex, is more distinct from the abdo- 

 men, and supports two superior limbs. These 

 acephali, too, are twins, at least in the greater 

 number of the cases. They are often not 

 full-grown, and borne by women who have 

 frequently been pregnant. The placenta is in 

 general common to the two foetuses, but 

 with two cords. The thorax is more perfect 

 than in the fifth type ; the upper part of the 

 body terminates not in an obtuse end, but in a 

 broad and flat surface, havii g a fissure in the 

 midst, with an indication of a head. The 

 sternum is often rudimentary, and the osseous 

 frame of the superior limbs is very incom- 

 plete. To the spinal column are added cervical 

 vertebrae, and sometimes a confused indication 

 of cranial bones. There is usually a dia- 

 phragm, but neither heart nor lungs. There 

 are commonly two vascular trunks, an arte- 

 rial and a venous. With the venous is con- 

 nected the umbilical vein ; and from the in- 

 ternal iliac arteries arise the umbilical arteries. 

 There are uropoietic organs, and an intestinal 

 canal, with a ca?cal termination ; and some- 

 times a liver. This latter is, however, some- 

 times wanting, together with the spleen and 

 the pancreas. In the intestinal tube there is 

 no meconium, but only a mucous substance. 

 The nervous system is very incomplete; but 

 there is constantly a spinal marrow with the 

 abdominal part of the sympathetic. I have 

 observed distinct muscles, of which the pre- 

 sence has been denied by others. 



Seventh Type. Acephali in which some 

 cranial bones are found. This has been 

 observed by Herhoklt, in a monster, born 

 twin with a well-formed child, of a mo- 

 ther who had five other children. There 

 was an amorphous head, with an indication 

 of eyes and nose, but without ears and 

 mouth : the rest of the body was much de- 

 formed. Of the cranial bones, the condyloid 

 and vertical portions of the occipital only 

 could be distinguished. There was no trace 

 of facial bones. Analogous observations have 

 been made by Curtius and Otto. 



Eighth Type. Body and extremities per- 

 fectly well developed, and having a neck, which 

 is wanting in the other types. The neck is sur- 

 mounted and terminated by the ears. This is 

 the form to which Gurlt gives the name of 

 peroccphalns aprosopus. I have met with 

 it in the lower animals only. The body and 

 the limbs are perfectly well developed; on the 

 perfect neck are placed two coalesced ears, 

 behind which there is an imperfect cranium, 

 composed principally of the cranial, minus the 

 facial, bones. In all this the deformity makes 

 a transition towards an imperfect formation of 

 the face. (Figs. 620, 621.) 



Ninth Type. Acephali which are composed 

 of the trunk only, without the least indication of 

 superior or inferior limbs. Only one case of 

 this monstrosity is known, observed by Vallis- 

 neri. In a foetus of a very mature period of 



