18 MARINE FAUNA OF ST. ANDREWS. 



Subkingclom CCELENTERATA. 



Class HYDEOZOA. 



The Hydroid Zoophytes of St. Andrews are chiefly pro- 

 cured from the deep water of the bay^ though a few appear 

 between tide-marks. Many are found in great profusion. 

 Compared with the southern shores, as at Devon and Corn- 

 wall *, the majority of the Hydroids are equally common in 

 both localities, some occm- more frequently in the one than 

 in the other, while a third series is more characteristic of 

 each area. Thus Sertularella rugosa, Sertidaria cujjressina, 

 Thuiaria thuja, and lialecium muricatum appear to be more 

 abundant at St. Andrews than in the south ; on the other 

 hand, Sertidaria argentea and Obelia dichotoma are probably 

 more plentiful in the latter, together with the appearance of 

 Tubularia at the extreme margin of low water. Tlie cha- 

 racteristic forms in the south are Corymorpha nutans, Aglao- 

 pkenia pluma, A. pennatula, Ophiodes mirahilis, Diphasia 

 pinnata, and an abundance of the species of Plumularia. At 

 St. Andrews Sertularia filicula, S.fusca, Tubularia coronata, 

 Cuspidella humilis, and Halecium labrosum afford distin- 

 guishing features. Moreover, instead of the tufted Clava 

 squamata, so common on the littoral Fuci of the western coast, 

 we have C. multicornis at St. Andrews on the under surface 

 of stones ; the splendid Corymorpha nutans of the sandy voes, 

 and the rich tufts of littoral Corynidte and Gonothyrcece of the 

 Zetlandic region, are likewise wholly absent. Amongst the 

 Hydi-omedusas, Sarsia prolifera, Forbes, occurs occasionally, 

 and Thaumantias pilosella, Forbes, in great abundance on the 

 surface of the bay in autumn. 



The habit of the zoophytes affords many interesting facts, 

 especially in regard to the profusion of parasitic structures. 

 The roots of the polyparies spring from diverse shells, stones, 



* J. & R. Q. Couch, in their ' Cornish Fauna ; ' the elahorate catalogue 

 of the Rev. T. Hiucks in the ' km\. & Mag. Nat. Hist' 18G1-62 ; and 

 Mr. Parfitt's Devonshire Catalogue published in 1866. 



