638 Bll. p. CHA.LME11S MITCHELL ON THE [DeC. 17, 



divisions are relatively narrow and do not touch at origin or 

 insertion ; the posterior division is in tendinous degeneration, an 

 apocentricity different from that found in the Eallidse. In Aramus 

 the condition is more Ealline, the posterior portion being extremely 

 lai'ge and reaching to the ilium, although the two divisions are not 

 in contact either at origin or insertion. In Psophia both divisions 

 are large, the posterior division having spread backwards so as to 

 take extensive origin from the ilium and from the thigh musculature. 

 At their insertions (text-fig. 75) they are far apart and quite free, 

 and along their course the edges are not in contact. In the Dicho- 

 lophidse both divisions are of fair size, the posterior division 

 possessing a backward extension to the ilium. Throughout their 

 course they are not in contact, and the insertions of the two 

 divisions are very far apart. In the Otididae the anterior division 

 resembles that in other Gruiformes, but the posterior division has 

 completely disappeared. In Bhhiochetus both divisions are strong, 

 the posterior having the Ealline backward extension to the ilium, 

 vvhile the insertions are well separated, that of the posterior 

 division being in common with the insertion of the humeral anchor 

 of the anconteus. In Eurypyga the condition is more archecentric 

 than that in Bhinochehis ; the backward extension has not reached 

 the ilium, and the insertions are much more nearly in contact. 

 The Helioriiithidse display the enormous backward extension and 

 great size of the posterior division common in the group. The 

 two divisions are free from one another and their insertions are 

 well separated. 



So far as this muscle is concerned, it is plain that the Grruiformes 

 do not display the exact coincidence of apocentricities found in a 

 compact group such as the Columbidae or the Alcedinidse, The 

 most striking apocentricity is the enormous backward extension of 

 the posterior division. This is best marked in the Rails, which 

 are diastatasic, and in NeUomis, which is eutaxic, but it appears in 

 all the eutaxic forms. In Eurypyga, which is diastataxic, it does 

 not occur; in the Crane, which is diastataxic, another apocentric 

 condition occurs, consisting in the reduction of the posterior 

 division, and this is carried to the extent of complete loss in Otis, 

 another diastataxic form. Among the diastataxic Eails two 

 conditions occur for which parallels have to be sought among the 

 Eatites. 



Latisbimus dorsi metapatagialis. — This muscular slip is present 

 in all the Gruiformes. It is superficial to the posterior division of 

 the latissimus dorsi and runs to the skin in the region of the axilla. 

 Owing to its superficial position, it is easy to overlook it, or to 

 remove it accidentally in process of skiiniing the region. 



Bhomboideus superjidalis et profaudus. — Both muscles are 

 present in all the Gruiformes, and the general course of the fibres 

 is that those of the superficial muscle run nearly transversely from 

 the scapula up towards the vertebral spines, but show a tendency 

 to slope backwards from below upwards. The fibres of the deep 

 muscle run ui)\Aard* and forwards from the scapula to the vertebrae. 



