282 Rev. S. Haughton on the Muscular 



Microphysa^ Westw., was rejected because the characters laid 

 down were drawn only from the female of one species, differing 

 greatly from the male, while those oi Zygonotus^ Fieb., included 

 both male and female. 



The remarks about Hydrometra and Gerris appear to be well 

 founded, the majority of authors having overlooked the fact of 

 the priority of Latreille's generic name Hydrometra for the 

 species stagnorum. Even Burmeister has done so ; for in a 

 note under LimnohateSj a genus he established for this species, 

 he says : — " Die Aenderung des Gattungsnamens wurde 

 dadurch nothig, dass ich den Namen Gerris fur die von Fabri- 

 cius in diese Gattung gestellten Arten beibehalten zu miissen 

 glaubte, da er das Recht der Anziennitat fur sich hat." Hy- 

 drometra, Lat., should be the generic name for stagnorum, and 

 Gerris, Fab., be restored to the species of Hydrometra of 

 authors. 



In these remarks we have been careful not to travel beyond 

 the record. The argmnent touches only a few points on the 

 surface of a great subject (the real signification of genera), 

 about which no two authors are agreed. The so-called " ana- 

 lytic method," for instance, so much in favour, tends to the 

 infinite multiplication of genera ; so that we are in danger of 

 realizing the tamit of Curtis " that every species would con- 

 stitute a genus," or of going a step further, and, by adopting 

 Amyot's " systfeme mononymique," which gives to every 

 creature a new and single name, abolish genera altogether. 



XXXVII. — On tlie Muscular Anatomy of the Alligator, By 

 the Rev. Samuel Haughton, M.D., F.R.S., Fellow of 

 Trinity College, Dublin. 



[Plate X.] 



In the sixteenth volume of the 'Annals of Natural History' 

 (3rd series, p. 326) I published an account of the muscular 

 anatomy of the leg of the Egyptian Crocodile (1865). Since 

 that time I have had an opportunity of studying the anatomy 

 of the Alligator of the Mississippi (June 1866). The specimen 

 dissected by me was a female, upwards of 6^ feet in length. 

 Its examination confirms, in most respects, the conclusions at 

 which I arrived from the dissection of the smaller specimen of 

 Crocodile previously described ; and I believe the results of 

 my dissection are worthy of being recorded. 



Mr. Hair, of Edinburgh, has kindly forwarded me a copy of 

 a paper on the Alligator, read by him as a thesis in the Uni- 



