174 MR. A. D. MICHAEL ON AN [Mar. 5, 



The hypohrancliials are elongated and, save for their anterior 

 curvature, almost straight. 



The ceratobranchuds are slightly broader osseous palettes than 

 in F. erithacus, and thev are hardly as much curved. 



It is interesting to find that this part of the anatomy of 

 Stringops would alone suffice to declare the essentially Psittacine 

 nature of the bird. It also proclaims it to be a peculiar Psittacine 

 form. With no affinities whatever for the Loriidae (so far as I 

 have yet been able to examine that family), it is also very distinct 

 from Psittacus. I have not been able to find any representation 

 of a Psittacine hyoid to which that of Stringops shows any marked 

 resemblance. 



In conclusion I think we have, in the existence of the parahyal 

 arch, a very distinctive character for at least three genera of 

 Loriidae ; and, when we consider how closely allied other genera of 

 that family are to Lorius, Eos, and TricJioglossus, we may, I think, 

 expect to find that a general resemblance exists between the 

 hyoids of the entire group. In other skeletal characters there are 

 some interesting differences between Psittactis and Lorius, as I 

 hope to be permitted on some future occasion to point out. 



2. A Study of the Internal Anatomy of Thyas petrophilus, 

 an unrecorded Hydrachnid found in Cornwall. By 

 A. D. Michael, F.L.S., P.R.M.S., &c. 



[Eeceived February 27, 1895.] 



(Plates VII.-IX.) 



Contents. 



Page 



General Observations aiKl Habitat 174 



Description of the new Species 176 



The Integument 178 



The Dermal Glands 179 



The Alimentary Canal and Excretory Organ ISO 



The Salivary Glands 188 



The Male Genital Organs 192 



The Female Genital Organs 194 



The (so-called) Genital Suckers 195 



Glands of unknown Function 197 



The Palpal Organs 198 



The Nervous System 199 



The Respiratory Organs 203 



Bibliography 205 



Explanation of the Plates 205 



The beautiful Acarid which forms the subject of this paper was 

 discovered by my friend Mr. E. Bostock when we were collecting 

 together in the" neighbourhood of the Land's End, Cornwall ; I 

 have since met with numerous specimens in the same locality, but 

 have not hitherto found it elsewhere. So far as I have been able 

 to ascertain it has not been previously observed, and is unrecorded. 



